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No. 40 of this Department treats of farm drainage, and more detailed 
information can be obtained from various publications on the subject. 
In the ordinary condition in which tidal marshes are found it is unwise 
to place tile until the land has had opportunity to drain and settle; 
otherwise in the settling the tile will be displaced and rendered of little 
use. For this reason the ditches for the tile drains should be dug and 
allowed to work as open drains until the excess of water from the soil 
and the settling which accompanies the drainage is over. In cases of 
very peaty swamps this sinking is great and continues for a long time. 
More permanent open drains are then essential, but they should be 
maintained as open drains no longer than necessary. 
The distances between the drains will vary with the soil. In light 
porous soils a distance of 300 feet is allowable, while in stiff and tight 
clays drains 30 feet apart are sometimes necessary. The minimum 
depth should be 3 feet for general farming or trucking, but for grass 
land the drains are as effective if placed not deeper than from 18 inches 
to 2 feet. In peat soils drains one-fourth to one-half mile apart are 
often sufficient. 
The grade on which the tile is to be laid is largely to be governed by 
the height of the marsh above low water. The tendency is to use very 
few of the 14-inch or 2-inch tiles, but to make 3-inch tiles the smallest 
used. The smaller tiles are found difficult to lay and keep in operation 
and the 38-inch tiles are not more expensive in the end and are much 
more effective. 
WASHING OUT THE SALT. 
_In salt marshes the tile drains are for two purposes: First to remove 
the salt which has been left by the water, and second, to remove 
promptly any excess of water which may be present or fall on the marsh. - 
In order that the salt may be removed it must be dissolved in water and. 
that water drained away. The usual way of reclaiming the meadows 
is to allow the rain to wash out the salt. This is a slow practice, requir- 
ing usually two or three years, but during this time some crop can 
usually be grown. The sweetening can be accelerated by irrigation 
with fresh water, if such is at hand. When the land is to be reclaimed 
by irrigation small amounts of water should be applied at frequent 
intervals rather than a single heavy flooding. If small applications of 
water, not more than enough to cover the ground to a depth of from one 
to 4 inches, with sufficient time between the applications to allow the 
drains to carry away all the excess of water, be applied, the land can 
be sweetened in one season or less. If the natural sweetening process 
is followed, the native salt grass should be allowed to grow at first and 
tame grasses will gradually take their place as the salt is removed by 
the drainage. : 
When the cost of this method of frequent small floodings is found to 
